We have added a Windows 2003 Exchange 2003 domain controller server to a
former NT Exchange 5.5 PDC domain. The Windows 2003 server is now the PDC
and the NT Exchange 5.5 server is not a domain controller. We have moved 6
mailboxes over to Exchange 2003 server and the remaining are still on
Exchange 5.5. The mailboxes that have moved over to 2003 can be accessed by
their corresponding users. However the domain administrator can no longer
access them. In the permissions on the mailboxes the domain administrator
has inherited rights for full access listed but also has "Denied" full access
listed and is greyed out. Exchange users who still have their mailboxes
residing on the Exchange 5.5 server can access the mailboxes on the Exchange
2003 server. Other users who have already had their Exchange mailboxes moved
over to the 2003 server cannot access other mailboxes moved over to 2003
server. However users who still have their Exchange mailboxes over on the
Exchange 5.5 server can access the mailboxes moved over to the Exchange 2003
server. The most important thing is to have the 2003 administrator access
these mailboxes once they have moved over to Exchange 2003 and then also to
allow users to be able to access each others mailboxes once they have been
moved over to 2003.